sarcastically roll your eyes and mumble, "I really, really wish I could..."

whats a half nelson

That is a threat i use on my friends and viewers, that if they dont pay attention or if they bug me, i will make them disappear. it gets a laugh or two, then on with the show. i use it randomly as well, like when i am at school and i am being bothered. So far i have lost 2 friends and 3 specs, since i forgot how to bring them back.

kid: Make me disappear!

magician: who said that? I can't see you! you've already disappeared to me... (Then ignore him. Smarter kids will get the hint usually.)

Or

magician: Where would you go and how would you get back?

Or

"Only if you can tell me the secret place disapearrees go! " (You will usually end up in a discussion where the kid yells out places. Answer them them with "Too many people there" or "Nobody ever goes there" "Come on, really! Where?" Then say, "You're just guessing and wasting time I can use to show you another fantastic trick."

I haven't read this entire thread...but here's what I usually do. In most cases someone will ask me, "hey, can you make this person disappear". I immediatly respond with, "how much money do you have". This joke, of course, can be milked as much as you'd like..."because for enough money, I can make just about anything disappear".

I don't want the possibility of getting sued by your parents, because I don't know if you'll ever comeback.

OR

If I do, you will be eternally banquished to a land without junk food.

find out who his freinds are a tell them to ignore them all day ( tell them why you are asking them to do this of course and then next time he asks say ok and than do some magical gesture and or words and just walk a way and ignore him then when his friends appearantly "dont notic him" all day edited start to freak out.